write a sample definition for each word/phrase to learn how it is used in context.

Use the English dictionary :

http://dictionary.cambridge.org/dictionary/british/

1.anniversary
2.ask someone out
3.blind date
4.break up with
5.fall in love
6.get divorced
7.get engaged
8.get married
9.go Dutch
10.go on a date
11.go out with someone
12.go steady
13.have a crush on
14.have things in common
15.love at first sight
16.meet people online
17.propose
18.stand someone up
19.turn someone down
20.wedding